Issue 42

P. Ferro et alii, Frattura ed Integrità Strutturale, 42 (2017) 189-195; DOI: 10.3221/IGF-ESIS.42.20 189 The fatigue behavior of V-notches in presence of residual stresses: recent developments and future outcomes P. Ferro Department of Engineering and Management, University of Padova, Stradella S. Nicola 3, 36100, Vicenza (Italy) ferro@gest.unipd.it M. Peron, S.M.J. Razavi, F. Berto, J. Torgersen Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Richard Birkelands vei 2b, 7491, Trondheim, Norway. mirco.peron@ntnu.no, javad.razavi@ntnu.no, filippo.berto@ntnu.no , jan.torgersen@ntnu.no A BSTRACT . Residual stresses, arising from welding processes or non- homogeneous plastic deformations, broadly influence the high cycle fatigue behavior of mechanical components. The presence of V-notches leads to singular residual stresses ahead of the notch tip and the asymptotic stress field can be described by the notch stress intensity factor (NSIF). However, plastic effects induce redistribution of residual stresses during cyclic loading and this variation is accounted in several numerical models developed for the calculation of the residual NSIFs. Due to the development of these models, the fascinating issue of predicting the fatigue strength of pre-stressed notched components has gained widely attention by the researchers and new approaches were recently developed and some of them are here reviewed. K EYWORDS . High cycle fatigue; Residual stress; V-notch; Fatigue strength. Citation: Ferro, P., Peron, M., Razavi, S.M.J, Berto, F., Torgesen, J., The fatigue behavior of V-notches in presence of residual stresses: recent developments and future outcomes, Frattura ed Integrità Strutturale, 42 (2017) 189-195. Received: 15.06.2017 Accepted: 21.07.2017 Published: 01.10.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION t is widely reported that static and fatigue strength is affected by geometric variations, especially by sharp V-notches [1-5]. Starting from Williams’ research [6], several works were written about the effect of local stress field rising from singularities, especially on fatigue strength of welded joints, that can be quantified by means of local Strain Energy Density criterion (SED) averaged over a control volume of a critical radius R C [7-11] or Notch Stress Intensity Factor criterion (NSIFs) [12-16]. Intensity and distribution of residual stresses are difficult to be quantified near the weld toe, and, moreover, residual stresses are related to welding parameters, geometry, clamping conditions, applied stress and number of cycles. As a consequence of these drawbacks, works reported just above include residual stress effects in reference curves built up from several experimental data. Despite of these complications, several numerical models were developed in order to describe the residual stress field near the weld toe, but Ferro et al. [17] were the firsts to reveal the asymptotic nature of residual stresses. They described how stationary and transient thermal loads affected thermal and residual stress fields, I